There are 9 justices on the court now: one Chief Justice and eight Associate Justices. Courts are unofficially named for the Chief Justice; the current Court is called the "Roberts Court" after Chief Justice John Roberts.

The Supreme Court chooses which cases it will decide on. Many people ask the Supreme Court to decide their cases, but the court refuses most of them. For the Supreme Court to decide a case, the case must be about federal law or be about the laws of more than one state. Cases must first be decided by a federal District Court and a federal Court of Appeals or by a state supreme court. Even after that, the Supreme Court can choose not to decide a case for any reason. There are some cases that can start in the Supreme Court and that the Supreme Court must decide, but those are usually rare.

The justices serve for life unless they want to retire earlier or are impeached. If a justice retires, he or she can still be asked to serve as a judge on a federal Court of Appeals. New justices are nominated (picked) by the President of the United States, and then must be approved by the United States Senate.